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Do the Math Turns One: Place Your Orders

One year ago today, Do the Math was born with a post on the absurdity of continued growth—in this case illustrating a Galaxy-consuming civilization in a mere 2500 years. Within a month, the site was getting thousands of pageviews per day, as I cranked out a backlog of thoughts and analysis surrounding the energy challenges we face.

In the process, adhering to a weekly schedule forced me to perform many new calculations on topics I had not previously explored very deeply. So besides being a cathartic experience, I gained new understanding, finding the exercise of constructing the alternative energy matrix to be particularly clarifying. One of the major lessons for me has been that while the physical scale of any alternative energy resource is important—and sometimes a showstopper—more often it’s the practical limitations that form the biggest barriers.

Finding the time and (mental) energy to keep the blog rolling has been challenging, but it’s you folks who inspired me to keep trucking. Knowing that each post would be read by thousands, and knowing that I could look forward to some excellent and thought-provoking (although sometimes just provoking) comments made the enterprise worthwhile.

At this point, I have dropped the cadence to bi-weekly, and my list of future topic ideas is slowly being whittled down. Many comments in the past have requested that I write a post about issue or another. I invite you to submit requests (even if repeated) in the comment forum below. Note that I might not have the background, interest, or time to invest if serious analysis is required. But there is some chance I’ll take the bait—and the idea may already even be on my list! Please refer to the Guide to Posts for a refresher of what’s been covered already.

Also, I think it fitting on this first anniversary to extend a note of gratitude to Asher Miller of the Post Carbon Institute for inspiring me to start writing, and for putting me in touch with the fine folks at the Energy Bulletin. The EB editors: Bart Anderson, Kristin Sponsler, and Simone Osborn offered early guidance and good advice (plus instant readership) that was vital to getting Do the Math off the ground. So a hearty thanks to these folks! 1.5 million pageviews later, their contributions have clearly had an impact.

And thanks to you, the readers, for your role in making this a successful and rewarding endeavor.

104 thoughts on “Do the Math Turns One: Place Your Orders”

I often send people here that are delusional or misinformed about alternative energies. Most often I tell them to read the galactic scale energy post first. It would be nice to have a post that was a sort of landing place for people that need to be educated on the reality of the energy situation. Take it from the perspective of someone who may have a vague understanding of peak oil, and subcribe to the “technology can save us” mentality. Offer them the facts and links out to posts where you go into detail on specific subjects.

One interesting point to focus is the amount of Net Energy that the Oil Industry is really giving to society nowadays. Despite the oil production is more or less stable, the fact that they need to drill in more remote places and use oil with less quality is surely decreasing its EROI as a whole. Perhaps the Net Energy peak for Oil was achieved a decade ago. Do you have information about this?

I would be interested in the energy efficiency of the food system:
* energy inputs on the farm (sunshine, fertilizer, tractor fuel etc),
* energy inputs in processing/distribution (transport, processing, cooling, supermarkets)
* losses and waste in processing and distribution
* energy efficiency of transformations (e.g. grain to beef, or seeds to oil)
* energy output of food (calories on the plate)

Firstly, thank you for all your writing – its been a blessing to read. Also exciting to see someone of David McKay’s (of Sustainability without the Hot Air) calibre pick up the mantle for the US and do some relevant calculations Stateside.

The things that I’ve been thinking about (and would love to see you write up) are as follows:
1) The business side of this equation – one of the things that both you and McKay tend to skip over are the economics of this shift. I’d love to see you provide commentary on a) where public policy can make a difference (carbon taxes, investment discount rates etc.) and 2) where there might be opportunities for entrepreneurs (solar is one obviously, but others that you can see). This might require some guest input, but the reality is that most countries are market-focussed, and the implementation of much of this will be driven by the private sector. This could end with an action for those who are inclined to take action.
2) There is increasing literature/data on the embodied energy/emissions in products, both consumer and otherwise. Much of your analysis has been end-consumer (households etc.). While I know you might loathe to dig into the energy used in supply chains, there is massive amounts of energy used in production and consumption of goods. You mentioned this tangentially in a number of posts (namely, ‘buy less stuff’) but providing some numbers behind this (ie. the embodied energy in an iPad/dishwasher/car) would help readers really understand. Think your ‘Flex-Fuel Humans’ post but for consumer goods. There is a great book from Elizabeth Grossman called High Tech Trash that covers the energy used in the production of consumer electronics that covers much of this (but not all) well. Key to understanding overall energy consumption (and therefore lowering it) is quantifying all stages of the energy chain.
3) A supplementary reading page – you list some good supplementary readings on the right hand side column of the main page, and then interspersed throughout comments in posts (Collapse by JD etc.) etc., but it’d be good to have a page that covers all of them in one place, much like your Post Index.
4) Finally – in the crazy, big goal sector: make a DECC 2050 pathway calculator (http://2050-calculator-tool.decc.gov.uk/) for the USA to be used in public policy discussions, then work with an organisation like AmericaSpeaks (or one of its equivalents who have a strong track record of citizen engagement) and organise an informed, bi-partisan discussion regarding energy pathways on a large scale. I’m pretty sure you could get funding for this and it would get people talking in a serious way about these issues. Email me directly if you want to talk more about this – I have some ideas and contacts that may be able to help.

Tom,
I’m sure I’m not the only one that appreciates the effort you have put into this blog. Congratulations on a blog well executed sir.

So, it sounds as though you might be suggesting that this blog has reached “peak subject matter”?

In terms of a suggestion for a future post, what about a bit of an extension to “Ruthless Extrapolation”?
Specifically, to what extent does a possible over-reliance on Gaussian mathematics contribute to “ruthless extrapolation” or to an overly-naive understanding of the world?
Does Mandelbrotian mathematics provide better mechanisms for modeling risk and extrapolating trends?

Nassim Nicholas Taleb gets into some detail on this subject in his book “The Black Swan”. It would be interesting to hear someone else offer a perspective on the same subject.

I’d be interested in some calculations about viability of solar installation in a multi-family buildings. Living in a city I don’t have so much freedom and I wonder if I would be able to gain anything sensible by installing SOME solar panels and batteries on my terrace which is about 50 sq. meters.

Do they have the same thermodynamic constraints of heat engines? Intuitively they don’t look like heat engines, and they operate at much smaller temperature gradients, but my intuition could be wrong and there might be some deep sense in which they are really heat engines with a Carnot cycle efficiency bound. I would appreciate your view on that.

Also, besides thermodynamic considerations, are there practical hurdles to large scale deployment of fuel cells? The costs of the precious metals catalysts is the first thing that comes to my mind.

A great foreword to this would be the link between energy and the world’s economy. And as someone mentioned earlier, your take on the business side of energy would make an interesting read. Anything that could shed light on what the specifics of why there isn’t some kind of natural transition to steady states.

Something else to write on: Italy’s energy per capita, or the energy use of any country with a net population growth ~ 0. If all populations level out, does energy level out as well?

Thanks for providing this! So ignoring the recent economic upheaval of 2008, the trend is clear that total energy keeps climbing.

In particular, Italy’s population is flat from 1980 to 2000, while energy climbed 30% (1.3% annual). A cherry picker would focus on the 1983 to 2003 trend, at 1.75% per year. But whatever. Absolute energy has tended to climb on top of flat population. Same story for Japan.

Thanks so much for all your hard work in making this blog so entertaining and useful.

I would like to second the request for more ‘embodied energy’ posts, and generally more posts that compare two behaviors and determine which one is the least energy-intensive (when comparing both manufacturing energy and usage energy over typical lifespan).

Examples: To keep cool while driving, is AC or rolled-down windows better? How much more fuel efficient does a new car have to be in order to justify replacing your old one? Would it be worth it to connect your fridge to a heat-pump so that you dump its heat outside in the summer and use the cold outside to your advantage in the winter?

I feel like many people want to ‘do the right thing’ but don’t have simple rules/answers about what the ‘right choice’ is.

The series about various energy sources is excellent. Have you considered making it into a book? I would buy it. Also, as a book, it would stand a bigger chance of being translated – I live among people who don’t want to spend their time reading English articles on WWW, but might try a translated book.

Yes. DO THE MATH in a book would be great. My manila folder of all the printed off posts is so unhandy. I have a difficult time reading off a screen for extended lengths of time.
Here in south Arkansas, we have various projects with climbing vines and with shade cloth to reduce the heating of our buildings from direct sunlight. We love shade trees but the recent derecho showed the down side of that approach. Vines on wire support systems are very interesting and effective in reducing heat gain and a/c energy use and they suck up some CO2 in the process. They also don’t have much mass to fall on your head in an extreme event. Do The Math on shading would be very interesting and also applicable to the urban heat effect. There are so many homes with no shade which is very serious when the power and a/c goes off. Thanks for al the good info. I have my credit card ready to order the book.

I would love to read a discussion of (carbon neutral) synthetic fuel. Maybe a reaction or response to Karl Littau’s google tech talk? http://www.youtube.com/watch?v=-KGjxsgCMig I believe the basic idea is:
1. capture CO2 from the atmosphere (air + electricity + catalysts -> pure CO2)
2. perform electrolysis on water ( water + more electricity from a
non-fossil fuel source -> hydrogen)
3. hydrogen + CO2 + catalysts/creating the conversion conditions -> methanol
4. drive cars running on methanol, releasing the CO2 back into the atmosphere
If we had a good enough way of accomplishing step (1) and used, say, solar power to generate the electricity needed in the various steps, how possible is this? How far away from being possible is this? Could it ever be practical?

Grr, pages that insist on javascript to display. And say so by redirecting to another page, so you can’t just turn JS on and reload.

Green Freedom looked neat, but the proposal seemed to assume building nuclear power for $1/watt. $5 billion plant cost, about half of which going to 2 GW of nuclear power. The newly licensed plant in the US is $7/Watt. I sense a problem.

Green Freedom is just one idea…I just watched the video G posted and it’s very interesting. The guy works on this at Xerox PARC of all places. He says the fuel production is established technology, about 50% efficient from CO2 to methanol, then if we go to gasoline I think it was about 40% overall. Extracting ambient CO2 is quite cheap in energy terms at the thermodynamic limit, and he’s hoping to get within a factor of two or three.

As for Green Freedom, bear in mind it would use thermal energy directly, rather than losing 60% or so in a turbine. That said, as Tom’s shown, conventional nuclear wouldn’t do the job at scale anyway. Advanced nuclear would, and some of the designs, like liquid thorium, have the potential to be significantly cheaper. Time will tell.

So if you have enough energy to synthesize the fuel, it’s not that much harder to get the carbon from the atmosphere and close the loop. Plus some more to get the hydrogen, I don’t know what portion that would contribute.

But we’d need at least twice as many power plants to make all our liquid fuels this way.

I’d like your opinion on this as well…
Methane production sounds like a possible solution for transportation and storage. It sounds much more feasible than the hydrogen economy since hydrogen storage is so difficult.

I’d like to see something along the lines of what features a net zero house would require (what area of solar panels, amount of batteries, solar water heating, insulation, etc). It could be a good way to bring together a lot of the things that you’ve already discussed into a more practical guide. Of course there is no one best way to solve this problem, but getting an idea of the scale of things would be fun. For fun, you could include an analysis of an underground house.

I’m also interested in some more detail on some subjects. For instance, when installing a PV array, one is usually advised to tilt the panels toward the equator at the co-latitude. But is this really the best for maximum output when considering secondary effects such as the refraction of the atmosphere, stronger absorption of light as it takes low angles through the atmosphere, etc?

Your starting essay «Galactic-Scale Energy» was great. Your essay «The Energy Trap» was the most appropriate regarding the developing situation our civilization is working its way into. I have no inkling of what you might do to approach that, let alone top it.

The many essays on «technical fix» solutions to the developing situation are great. They remind me of the kids’ summer camp song “You Can’t Get to Heaven” (e.g. one my daughter brought home in the 1960′s: “You can’t get to Heaven/ In a Kleenex box/ Cuz God don’t like/ No dirty snots”), which is so subtly and eerily relevant. But doing math is like a compass & astrolabe: informative approximations on where we are and where we’re currently heading, but too limited in where we should be going and how to get ourselves there.

Very humbly, I suggest considering a Mark II on where («where» is a plural noun here) we should be going and how we might go about getting there.

Are there other resources that have experienced this pattern of utilization, similar to the cheap energy boom? I’m thinking herds of wild game, land rushes, etc, and what happened when scarcity set in? What did the economic adjustments look like. Obviously there hasn’t been anything on this scale, but there should be something.

I would like to read what physics and mathematics has to say about the limits of nuclear energy and battery storage, too.

I think it would also be interesting to know what kind of scale issues would be involved with reducing a one meter sea level rise by pumping sea water inland to reservoirs. How many Bingham Canyon Mines would it take to hold all that water?

Science fiction has often talked about terraforming planets. What are the physics and mathematics of terraforming the American southwest into an artificial rain forest to capture carbon dioxide? How much water would have it take to irrigate an area the size of Arizona with 150cm per year? How much energy would it take to desalinate it and pump it up to a 1km elevation? How much of that energy could be recovered by capturing the runoff in a hydroelectric facility?

Thank you for your great blog. Its unveiling of the immense scale of energy use in modern society has profoundly changed my worldview. I think if more people knew what an aberration (bubble?) our current energy-juiced lifestyle is, they would enthusiastically make an adjustment to something closer to sustainability. You, my friend, are a part of the solution.

Your excellent post on heat pumps complete skipped ground water heat pumps, that is heat pumps that use the near-surface ground as a heat source and sink. This gives a great boost in efficiency at a large increase in capital cost. What is the tradeoff?

Note that GWHP are not to be confused with geothermal heating which involves drilling deep enough to tap the internal heat of the earth, usually thousands of meters.

Congratulations on the first anniversary! Do the Math is indispensable. I share every post with friends and family. We are all very grateful to you for your hard work and great insight. Thank you, and congratulations again.

Congratulations.
I especially liked the post where each energy source was compared in practicability and potential. I liked the “Why not space” post too. I enjoy suggesting this site to other readers.

I am most concerned about full blown automation and the effects of peak oil happening at about the same time.
I know this is kinda far out, but here’s an idea…
Make a game out of it!
Possible outcomes would be based on energy, economy and the environment and be recorded. Some games end with ocean anoxia while others end up with societies based on clean energy automation. But how will the populace deal with machine automation that displaces most of the jobs?

Tom, this is a fantastic blog and I’m sure that whatever you decide to write about in the future will be worthwhile.

One thing I’d like to see is a thorough comparison of air travel and driving, showing the range of energy consumption per mile in each case, and how it depends on the distance traveled, vehicle type, number of passengers, and so on.

Perhaps you could share some home energy success stories from people living in cold climates. (A specific challenge: find someone who has successfully retrofitted an old house with active solar space heating.)

I don’t recall that you’ve ever shown all of your personal (home and transportation) energy consumption on a single chart, to highlight what the biggest contributions are. It would be interesting to do that not just for your household but for a variety of households with different lifestyles and in different locations.

I’m still troubled by the widely disparate estimates of available fossil fuel resources that I see coming from different sources. You’ve already written about this, but if you learn more, please share it.

It would be fun to see a debate over space resources between you and some of the more credible cheerleaders.

I’m still troubled by the widely disparate estimates of available fossil fuel resources

“available fossil fuel resources” is a meaningless phrase, it just means they detected carbon under the ground. What it would take to make it meaninglful is a statement of how much it would cost to get it out. You can then make a histogram of how much fossil fuel is available at each level of effort.

Bottom line, sources are tapped in order of how expensive they are. If it wasn’t more expensive than the sources they’re tapping now, they’d be tapping that source now.

What about an article about vertical farming and especially the energy expenditure one can expect?

I keep hearing that this “technology” will save us in terms of food and transportation problems but my common sense has serious doubts: Why would a vertical farming be less energy intensive and less expensive than an office building (and rents for commercial real estate seem prohibitively expensive for any kind of food production)?

We can only hope for a revolution in structural building materials based on something like carbon graphene and giant 3-d printers. Only then could we afford to live (and grow food) in vertically integrated cities. Of course, we would need to use such advanced machine automation to make the solar collection and storage cheap enough to support all of us in the first place.

Congratulations and gratitude for your dedication to this project. It is nothing less than an heroic effort to save civilization from collapse and thus easily more important than most Nobel awards.

I suggest doing a narrative- or bullet-format summary post that scrolls through your worldview as informed by these posts, with links, of course. This would be a great index for first-timers and an invaluable refresher for the rest of us – who’ve now read the equivalent of a lengthy, information-dense, paradigm-challenging book. Reinforcing its content this way would improve your and our EROEI.

Congrats on the year mark, this has been one of the most informative (and practical) blogs I’ve read online

Your last entry on TED, I was a bit disappointed was not an announcement of an upcoming TED talk you should formulate your excellent research into a TED talk, and get that published; this is exactly the kind of stuff they would love to host.

As for future directions of your blog:
A random idea, seeing that food prices are expanding rapidly and becoming somewhat unsustainable, it would be interesting to see what mileage you could get and thoughts on experimenting with growing your own food, in sustainable and low effort ways.

I get a feeling it’s already been touched upon already though, but not sure it’s had a dedicated article or experiments.

Tom, As an educator myself, a “glorified shop teacher” who has traveled across the country teaching Solar PV and Thermal power, I’ve always included in my introduction class some of the problems of scale all renewable generation systems face when compared to the inheritance we’ve been using from fossil fuels. I’ve stood in front of classes on day one running the same numbers you have – simply to get students into a less rainbows and unicorns mood so that we can tackle the subject realistically.

Rather than struggle to continue this blog, you might be better served by refining the past year’s worth of work into a realistic “Introduction to Renewable Energy” text, or similar book. Publish it yourself online… it’s a work that should be out there. That said, I wish you well and look forward to whatever you decide to publish, in whichever format.

Assuming (to one significant figure) a trillion barrels of oil consumed to date and another trillion still in the ground, a hundred million barrels per day currently consumed (actually about 85 Mbbl/day, but I said one significant figure), and an historical 2% annual growth rate (corresponding to a 35-year doubling time), that gives us three basic options:

continue our 2% growth rate (Hubbert peak be damned, and never mind increasing extraction costs, either) and suddenly run out entirely in a dozen years;
halt all growth (again, Hubbert be damned) and suddenly run out in 10,000 days ~= 30 years;
or start a 2% annual decrease (as Hubbert says we will), be down to ’70s-era petroleum consumption by mid-century, and all the way back to 1900′s consumption levels by the end of the century.

All three of those options should scare the hell out of everybody, and we simply don’t have any other options on the petroleum front. (Discover another trillion barrels? Yeah, right…and that just gives us an extra decade or three, depending on the scenario — and likely with much higher daily consumption at that point, to boot.)

So…what, realistically, can we do? How fast would we have to ramp up a mix of solar, coal, nuclear, fracking, whatever, to keep going? How aggressively do we have to switch the ground transportation fleet to electric motors? If we rely on those other petrochemicals (or even nuclear), all we do is drive ourselves to the 50% depletion disaster point for those resources that we’re at today with petroleum that much faster. Presumably, the end goal is a solar economy with (e.g.) Fischer-Tropsch synthesis of atmospheric CO2 for things like jets that absolutely need hydrocarbon fuels, but we’re going to need everything we’ve got to get there. How much coal will be left in the ground at that point?

And…what’s our margin of error in all of this?

I’m taking as my basic assumption that, at least for this transition, growth will have to continue at at least 1% – 2% annually for the foreseeable future…our society just isn’t capable of functioning any other way without major upheaval, and exactly that sort of upheaval is what would cause everything to come crashing down around our heads the same way peak oil threatens to. Maybe we can gradually transition to a steady-state economy at the same time we transition to a solar economy, but we’re certainly not going to shrink ourselves out of this mess.

Hi Tom, I’ve followed your series and must say thanks for the great work, a very clear perspective on our energy future. My interest is phase change material as a means of providing an efficient “thermal mass”, really a room temperature heat storage system for the light-weight North American built house or small building, a necessity for passive space heating and cooling. A comparison of say a calcium chloride hexahydrate material with concrete in terms of storage is enlightening mentally and structurally. Thanks again, Robert

How about “time”, and how we trade energy for time? Line-drying clothes saves energy, but takes more time. How much time? Sorting recycling may save energy (aluminum wins, at least), but takes time. How much energy, for the time? Riding a bicycle takes time, but saves energy (and within limits, is a dual use of that time, since we need a certain amount of exercise). How’s the tradeoff there?

An additional frob on these things that take time is that some of them take time now, and pay off later. Someone who gets a decent amount of exercise can expect to live between 20k and 50k hours longer, depending on gender and the sort of exercise. So time spent somewhat energetically, may not really be “time spent”. Hanging clothes is not the worst sort of exercise. Riding a bicycle for transportation scores very well (e.g., 4 hours/week commuting on a bicycle = 200 hrs/year. Depending on speed relative to driving, that may be 0-150 hours “spent” on exercise. If it’s 100, then 75 years of cycling “costs” you 7500 hours, but pays you back 20k to 50k, net of 6.5k to 26.5k after you account for 1/3 sleeping. But, again, what about the energy? Exercise, and biking in particular, uses enough human energy that we need to worry a little bit about food (covered elsewhere) and perhaps additional costs/savings related to clothing, cooling, and heating).

PS – re time spent. A lot of this varies by situation. Line drying clothes is less practical in humid climates, dead easy in deserts. Biking to work from an Atlanta or Houston suburb loses more on speed (and comfort) compared to cars than (say) biking into Cambridge (MA) from a suburb, where the bike is often faster at rush hour (I have personally measured this). Some municipalities do single-stream recycling, some do not, no idea how economies of scale work into this. Some places gleaners sort out return-deposit cans and bottles, and recycle them directly to various specialized stations, trading their time for (presumably) more efficient reuse. This is not that much different from how solar power is a slam-dunk in the lower latitudes, less so in the higher latitudes.

How much energy does it actually take to run human society? Several ecologists with whom I’ve spoken believe that it is impossible to sustain 7 billion humans on the planet over any real amount of time. Certainly soil loss, phosphate and other mineral and natural resource depletion each present challenges.

But what about from an energy perspective? Suppose we each lived using as little energy as possible, assuming significant drops in the standard of living (and factoring in natural migration AWAY from energy-intensive living environments like the Arizona desert, and re-cultivation of local soils). How much energy do we actually need, and how much of it will be need to find in the next 150 years with fossil fuel depletion proceeding apace?

I suppose my question boils down to this: from an energy perspective (leaving natural resources alone, although the increased extraction cost due to expensive energy is an inevitable consideration, along with the energy cost of replacing natural gas-based fertilizers) how many people can this planet expect to support over the next several centuries?

This question is really an expansion of Gidon Gerber’s questions (above) relating to the energy efficiency of the food system.

I tremendously enjoyed your blog and recomended it to several others. However, I think would be nice to have knowledge in book form (for people who’s attention span is longer offline than online.) Could be a dead tree or e-book.*

I know that editing a book is lots of work, so what I sugest is not easy, but I do think that it could spread the word even further.

* on that note: what consumes more resources: dead-tree or ebook?
cheers

As a fan of space exploration, I would like to read pretty much anything related to it, if you can still come up with interesting (post-worthy) insights about it.

As a supporter of nuclear power, I would like the same as above about it. And all kinds of energy-related stuff can of course be interesting in addition to nuclear power. For example, one other subject that comes to mind right now and that you have had pretty interesting things to say about, IMO, has been energy efficiency.

Sorry if this is too vague. Maybe the most common thing about everything mentioned above is the possibilities offered and difficulties faced by technology.

Thank you for the clear, concise analyses. As a person without much formal math or physics training, I appreciate your being able to lay things out in a comprehensible framework.

I’d love to see a post or just some commentary about how you relate in real life to all the technological cornucopians who love to talk about how this or that will save us all? Or the people who love to talk about how we have hundreds of years of oil left in the ground, atmosphere be damned? I find it hard to have a meaningful discussion about the future of energy with most people and you seem very thoughtful and adept at putting things clearly when it comes to energy.

I would also love to see a post on artificial photosynthesis, specifically if the stage of its development is anywhere near a useful application.

Thank you for bringing a clarity of thought and explanation to a widely mis-understood area (not least by me before reading many of these posts!).

I would love to hear your views on where the balance is likely to fall on the issue of land use. It seems to me that it’s more complicated than the simple “Food vs. Fuel” because of issues like bio-diversity and the networks that support life on the planet. Is basic science far enough advanced to make reasonable predictions in this area yet, or are we better off applying a precautionary principle and not making things worse until we understand more?

James, you wrote:
“Is basic science far enough advanced to make reasonable predictions in this area yet, or are we better off applying a precautionary principle and not making things worse until we understand more?”

I think this is a fantastic question to which I would reply with another question:
How would it ever be possible to determine whether human understanding was sufficient to NOT apply a precautionary principal?

A wise species would acknowledge that there are always “unknown unknowns” and would foster a culture of respect for and caution towards an uncertain future – emphasizing simplicity, redundancy and resilience rather than complexity, efficiency and fragility.

I know what you mean: what confidence level is “enough”? But I think it’s dangerous to take that to extremes, else you’ll get paralysing risk aversion. Given that I (and probably most readers of Do-the-math) believe that radical change is required to our energy production and consumption patterns, if we do nothing the forces of inertia mean that we’ll head straight off the cliff into 5 degrees warming.

First order approximation is that energy use of digital circuits is proportional to the square of the clock frequency. So what computing power/comunications capacity can we sustainably afford?
If software was rewritten to run on slower systems, what would be the optimal tradeoff between the one-time development cost and the recurring energy cost of running the systems?kdv

Tom,
Congrats to great posts. You are practical and I certainly appreciate that. I also find that many energy nerds have no economic sense (in a similar way that economic nerds – I believe most of them are called economists have no energy-sense). I try to marry these discussions – and also a discussion about global development in a post about manual labour versus oil in a post about our 250 million energy slaves. http://gardenearth.blogspot.com.br/2011/03/250-billion-energy-slaves.html.

I am neither a mathematician nor a physicist (or economist) and I would be very grateful if you could look at the foundations for that discussion and possibly add or correct to it.

I think some further posts on limits to growth would be good. You need to keep poking the infinite economists so that they are forced to rethink – some seem to continue to misunderstand the energy-growth link e.g. http://is.gd/93g0i3 claiming that you don’t understand growth when it seems to me that they don’t understand energy.

Also airborne wind energy is of interest to me (and I’ve mentioned it before on here). Not the stratospheric AWE, but the lower and medium altitudes – does that have the potential to change your views on the abundance of wind energy given that the effective rotor area of airborne wind turbines would be far bigger and the capacity factor would be substantially greater than for land based turbines? The technology also has the potential for very low embodied energy which makes it attractive. It’s early days though so there may not be a great deal to go on at the moment.

Oh and a further one: grid and domestic scale batteries would be a good one to cover. What developments are required in terms of cost and performance for these to take off? What are the implications for high penetrations of renewable energy?

An idea I have ben gnawing on for some time but have had a hard time to put into numbers was a solar boat. Assuming that they stand idle most of the time how large would the panel area have to bee to recharge until the next sunny weekend. What about milage? How many extra miles do you get from panels as they produce energy as you go?. How much further can concepts such as the turanor (continous boating with solar) or the solar impulse (solar airplane) go with technological improvements? Many roads to go, would apreciate reading about any of them.

How about a “Peak People” post?
Given the following assumptions:
Using only renewable/sustainable energy sources (wind, solar, geothermal, wood/plant material, etc) and todays technology (ie, barring significant advances in efficiency or new generation sources), and todays lifestyle/energy consumption per capita, what is the carrying capacity of the planet? What population can the earth sustain?

Congratulations and thank you for such an important, interesting and successful blog!

As one of your European readers I would like to request a comparison piece on energy per capita amongst different countries focusing on why any differences exist and what should perhaps be done about it. For instance a bit of googling tells me that the US uses 2-3 times the energy per capita as many European and East Asian countries*. This seems quite important to note as these countries are all developed nations but seem to have very different energy usages. I would suspect that this is due to size and cultural attitudes regarding transport which may point to a relatively simple ways of cutting energy usage.

In addition a piece on which countries are doing it right (or perhaps least worse) would be pretty cool.

Canada and Nordics use about as much energy as the US per capita. Climate matters, as do transportation infrastructure and home size. Japanese live in small homes, take transit a lot, and line-dry their clothes. Much of Europe is similar if less so, and has nicer climate than either Japan or the US. While it’s simple to describe the differences, making changes is a lot harder.

I went looking for posts on hydrogen a couple of weeks back (got into an online discussion with a friend), and was susprised to find no posts on it! Not because I think it is viable (and in practise relies on electricity generation so makes sense to not address it separately), but because there is still widespread belief that it is a solution to the energy crisis. Would you consider a post addressing the issues surrounding hydrogen as a form of energy storage?

And as this is my first time posting here, thanks very much for this blog by the way. Before finding it I had a tendency to the reverse of cornucopianism and tended to assume that nothing was viable and we were heading back to the dark ages, and reading this blog has made it clear that there are plenty of viable options for a future of modest energy use if we rise to the challenge.

Congrats, you have stumbled upon a hobby with a much pressure to publish as your day job! (I third (or fourth?) the motion for a book “7 Habits of Highly Efficient People”)

I am noticing that there are many comments requesting you to DTM on what sound like incremental extensions of previous posts. How about a “cookbook” post on how you DTM so that readers can satisfy their own curiosities. I think the biggest thing to stress is the importance of approaching a problem from two angles and seeing that the numbers from the two angles are in agreement at the end of the day.

I would love to see a post about using DC wiring in homes. LED lights want DC power, so do most electronics. Most renewables want to generate DC power. How much energy could we save by cutting out the ‘middle man’ (i.e. inverters, LED drivers, wall warts for computers, phones, stereos etc.)?

I have often thought about having a better middle man than removing it completely. Yes if you have solar on your roof that outputs 12v then you should run devices directly off the 12v that is being stored in batteries, etc.

But I thought that we can even have a nice savings by having a centralized ac–>dc conversion for the entire house. Most wall warts, phone chargers etc have only so-so efficiency especially with the “vampire drain”. Whereas larger dedicated ac–>dc converters are much more efficient. Take a large computer power supply such as: http://www.newegg.com/Product/Product.aspx?Item=N82E16817153156 it can hit 89-94% efficiency @ 20-100% load 230v ac –> 12v & 5v dc. Yes the efficiency only applies at certain watt ranges, but I think that problem could be overcome if it was not limited to the ATX size/wiring standards. So have one large ac–>dc conversion in the household that can power LCD tv’s, phones, computers, etc. I think the first thing that needs to be done though is to update the wiring standard to include a 12 power receptacle to make the transition easier. Of course once more devices actually support a native 12v dc plug it would be much easier to go directly from 12v dc batteries to devices. It would also help to standardize what dc voltage is used internally in devices as some use odd dc voltages like inkjet printers at 29v and other goofy voltages.

And for those who think ac–>dc conversion isn’t important should look at the devices around them because many have internal ac-dc conversion going on including: radios, lcds, desktop computers, speakers, inkjet printers, alarm clocks, phones, laptops, game consoles, cable boxes, etc.

I would like to read about the use of synthetic gas for energy storage. The idea is to use surplusses of wind and solar power to either create hydrogen from water or to create methane from water and carbon dioxide. These gases then can be fed to the natural gas infrastructure. The gases can be stored in huge amounts for month, it can be used, as is today natural gas, for heating, cooking, electricity production, even as a car fuel.

It is thought to be a cheap solution, because the entire infrastatructure for the methane is already there and even today in northern germany wind power stations are often switched off on windy days, because the demand is missing. Most people don’t see that intermittency goes two ways, you have either not enough or to much, and using energy that would otherwise be wasted is basically a free lunch. The storage is cheap to build, just flush some caverns into saltrock, many nations already have storage for natural gas for several month, so even large scale seasonal storage is possible.

How much gas production is needed to cope with daily and seasonal intermittency? How much energy gets lost during the process, using current infrastructure and new one (e.g. fule cells, whcih exist for both hydrogen and methane)? How much more renewables have to be installed to compensate the losses? What is more efficent, hydrogen, methane and a mix of both?

How does this compare to fracking (especially to those dying wells, that are a few years old)? How much natural gas is produced on a square kilometer of land using old fracking wells and what renewable infrastructrure would be needed to produce the same amount of sun gas or wind gas? It is possible to cover fracked lands with solarpanels or wind power stations and use the fracking pipes to feed in the gas?

First (because you have never heard from me before), a big HUZZAH for Do the Math. I recommend all my friends to the blog, regardless of their opinions on peak oil and energy issues, because I think your approach adds clarity (and sanity) to a discussion where it is sorely needed.

I want to second, and perhaps expand upon, some suggestions here regarding a DTM post on the energy of food. As a bit of a foodie and permaculturist myself, I would love to see you address some different dietary choices from a Calorie-counting perspective – note the capital “C”, as I am speaking not of the calories of heat energy we are _consuming_, but the kilocalories that are represented in the food we consume by way of production, marketing, transportation, and sale.

I have tried, and occasionally succeed, in growing my own food, and I can tell you this is not a simple as “eating vegan is more green”, or “pastured meat is more sustainable”. I do believe, and hope you and many of your readers appreciate, that the stored energy represented in fossil fuels is far too valuable to spend on sustaining an everyday need like feeding ourselves.

Hi Tom,
Maybe another idea for something to investigate:
I suspect that it is not a good thing to be too efficient, that it is possible for too much efficiency to be too much of a good thing or that efficiency is “good” as long as it doesn’t undermine the resiliency of the system in question.

An example of “good” efficiency might be to use the least amount of a resource as possible to accomplish a certain goal.
An example of “bad” efficiency might be to continuously consolidate the provision of a particular service until any disruption to the resulting provider results in unmitigatable disruptions to the system that depends on the service.
[As an aside, interestingly, the definition of the word "consolidate" often implies "stregthening" or making "more secure" which is at odds with the observation that centralized systems are less resilient than distributed systems.]

Although the examples above are abstract in nature, there are plenty of “real world” examples that could be substituted – including examples of the inverse, “good” INefficiency.

Is there a difference between “good” efficiency and “bad” efficiency?
If so, are there any clear guidelines that help us to know when we’re pursuing too much of a good thing or when we’re being prudent in our inefficiency?

Dear Mr. Murphy: I follow your blog from Spain and I thank you for its quality. However, I am missing more political level in its content, and as I think possible solutions to the problems we are worrying about need political implications, I suggest a post in this direction. How can we go for a stady-state society? What does it meant? Which are the political barriers we are confronted? From a rest of the world perpective we see this planet military occupyed by USA, with the clear goal of securing the american way of life, the least sustainable way of life. The north american citizens count for at least 25% of the problems we are talking about, so I miss an attitude more concious and responsible from your part.
Thanks again for the technical an literary quality of your posts and forgive my poor English.

Aside from complimenting the literary quality of DtM posts, your English seems just fine!

Kidding aside, you make a very interesting point. Here is a clip from a story set back in the George W. Bush days. While that presidency is over, the attitude survives in many:

But White House spokesman Ari Fleischer was adamant Monday when asked whether the president would ask Americans to stop using so much energy.

“That’s a big ‘no,’” Fleischer said. “The president believes that it’s an American way of life, that it should be the goal of policy-makers to protect the American way of life. The American way of life is a blessed one.”

When entitlement meets religious overtones and collides with resource limits in a wider world, watch out!

Twenty years ago President George H W Bush proclaimed “The American way of life is not negotiable.” That has been every president’s position ever since we taught President Jimmy Carter the lesson: American exceptionalism entitles us not to be deterred from our Destiny.

Thanks for the efforts. I really look forward to reading your posts whenever a new one appears.

Others may have posted this to you already, but I consider this site great (and humorous) for questions whose answers rely on physics. Perhaps reading it weekly will generate some relevant ideas for your blog. http://what-if.xkcd.com/3/

One question I wonder about is how much of (Earth’s) total energy production would need to diverted to support a very ‘modest’ human presence in the solar system, say 10,000 people. Your post on Why not Space got me thinking about this. The energy required to put the small number of people in to LEO we have now and keep them supplied is considerable, what if we were trying to do the same for the a much larger number, say 10k or so.

Another possible way to look at this is, what % roughly, of our world energy budget is goes to our space based efforts. Atm, I would guess? its not huge as most of it is un-manned, but I wonder how much that would change if any sort of serious effort to move large numbers of humans off planet were ever contemplated. We have studies where we can easily find out how much the average human consumes here on Earth, in N. America Europe, Africa etc and compare. Curious to know what an off-world colonist would consume just to stay alive and healthy, how much of that would need to come from Earth. I would think at some point, the energy requirements alone would force even a very modest effort to a rather early halt. Is there a basis for this notion

I’m not a space cadet by any means but this would be interesting. What would make it really interesting though is an analysis of the secondary effects of energy being so cheap (which would be necessary for such a set up to exist). In my experience cadets tend to work out how much energy it will take to fufill their dream and propose that accelerating development will bring that amount within reasonable economic cost but tend to forget how much energy that puts in the hands of an average person.

Simple back-of-the-envelop example; accelerating a 100 tonne vehicle to .9c would take 3.65e21J*. Currently that amount of energy would cost $100 trillion** which is more than the total world economy. If we play the space cadet technological optimist card we might argue that in the future that price will fall. Ok so let’s propose it falls to $100 billion. In this world $1 would buy you ~37GJ meaning that a country like the UK could power itself for $2 per second which corrosponds to $60 million per year which is roughly $1 per person per year.

Even letting the “magic future technology will solve this problem” argument slide the ramifications of the cheapness of energy in this world would be huge. Forget climate change circa 2012 with energy too cheap to meter by this extent we’ll open ourselves up to simply boiling the surface of the planet with our waste heat.

*That’s cheating of course because we’re just looking at the kinetic energy i.e. the absolute minimum. Taking into account the ideal rocket equation or working out the performance of a solar sail would blow that number even more sky high.

I would like to offer an idea for a potential post. Hopefully it’s not one that you’ve already done and I’m just unaware of.

The context is this: I wonder what I as an individual can do to slow and then stop climate warming. Since we’re not getting much action from governments and corporations, what can individual citizens do?

The question is this: What changes would the average household [in the US, I suppose] need to make to retard [and then reverse] increases in atmospheric carbon dioxide?

The answer would look like:
1. assume x, y, and z.
2. then each household would need to do: a) use # fewer gallons of gasoline per month; b) travel # fewer airline miles per year; c) use # fewer kilowatt hours of electricity per month; etc etc

Happy birthday! I absolutely love your blog. A book would be great. Have you come across the ecosocialist no-growth qpproach promoted by Climate and Capitalism website and by radical sociologist john bellamy foster? Also, economist Li Minqi in the last section of his book on China and the global economy (i forget the exact title) demolishes the idea that renewable energes such as solar and wind power can lead to sustainabity so long as the profit motive (capitalist relations) holds sway in society. Anyway, all the very best

Would love to see some numbers on what it would take to run cars on solar energy. There is surprisingly little out there, one way or another, on the practicalities of running a Chevy Volt (or pick your own electric car) only on energy from solar PV. I met a guy who works for an alternative energy foundation who said “sure, we could run all of our cars on solar energy.” That’d surprise me, but then I haven’t done the math.

Paul, many people are already doing this. Indeed several car manufacturers are loooking into co-operative deals with solar installation companies to offer both the car and a solar PV system as a package. Look at http://solarchargeddriving.com and /http://activeemobility.blogspot.com for some introductory information

The accumulated sunshine of millions of year will be burnt, no doubt. Is it worth? We have gathered a huge amount of knowledge about the world. Can this knowledge survive the collapse of our civilization? How much of this knowledge can be useful without the current industrial environment? Would a printed copy of current Wikipedia change the life of the people of the middle ages?

There is one variation on nuclear I’d like you to analyze: obtaining energy from so-called nuclear waste.

Used fossil fuel is indeed energetically worthless — pretty much everything that can react exothermically with H2O or CO2 reacts so much better with oxygen, which is free. (Except fluorine, but that would be a really bad idea…)

But “spent” nuclear fuel is only removed because it eats neutrons, slowing the rate at which the fresh fuel in a conventional fission reactor “burns”. Judging by the very problems we’ve had storing it safely, it still has a fair bit of energy inside, which it spontaneously releases, ready-or-not.

At its simplest, we basically put the waste in a cooling pool (like we have to do anyway), and then use the pool as if it was a low-intensity geothermal source.

plutonium and other actinides, resulting from neutron capture and beta or alpha decay by the U-238 that’s most of the uranium. The US tries to bury both; other countries reprocess, to take out the remaining U-238 and maybe the plutonium too. All of the actinides are, in theory, fuel in the right breeder reactor; if they have odd mass they’re fissile and if they have even number they can neutron capture and become odd.

The fission products are not fuel. They *are* ‘hot’ and radioactive, and emitting a lot of energy compared to chemical energy densities. OTOH, I think the energy density is 1% that of fission fuels. So given that you are using fission, and that the products are dangerous to handle, it may not be worth trying to use them for power. Most obvious would be to boil water with them, or re-heat water going into the main reactor, as you say… but these products are exactly what you really don’t want melting or catching fire in the event of a cooling accident. They’re the stuff we’re most scared of from Fukushima, or that gets called “fallout” from a nuclear bomb.

So putting them in a big *cool* pool and not messing with them may be the wisest course of action.

1. When I was getting my PhD in physics, the options to research were exclusively in basic research — valuable, but removed from most people’s daily lives. Your page connects physics and to regular life, much more than examples in textbooks I used, on issues that are important today that weren’t a few decades ago. I’d love to read what other physicists are treating things like this at what institutions with what results and if their numbers are growing. David MacKay seems another big one. Any others?

2. I’d love to see something on the carrying capacity of the Earth — what factors affect our understanding of it and how they are changing, of course, but also what happens the closer we get to it. I suspect that close to it, greater efficiency will make us more susceptible to large-scale problems since we will have interconnected bottlenecks for energy, food, water, and so on.

3. I’m curious about the amount of oil energy in the foods I eat. I’ve seen analyses elsewhere, but I’m curious to see your analysis of it. Food used to be completely solar powered. Now I hear some of it has more fossil fuel energy than solar. I’m curious about food and oil energy in its own right, but also in relation to the next topic.

4. Fossil fuels and the Green Revolution. What fossil fuel inputs does modern agriculture require? What happens if those inputs go away? I have a feeling the Green Revolution mainly enabled us to convert oil to food. People talk about it as saving lives, but I feel like it extended our ability to grow past where we could sustain ourselves without fossil fuels, accelerating our consumption of it and compounding the risk of collapse if we can’t find substitutes for oil. I’d love to see someone do the math.

5. Rhetoric: When I talk to people about the energy trap and related issues, I often get “People have been predicting the end of the world since the dawn of history. They all predict it. It never happens. It didn’t happen then so it won’t happen now.” How do you respond? I point out many civilizations have collapsed (as Jared Diamond wrote about) and things probably looked prosperous just before they did. I suspect you’ve had the conversation more times. I’m curious what you say.

6. Connecting behavior to what people care about. On a hot and humid day, for most people turning on the air conditioner is a rational choice. They feel more comfortable now for a few dollars later, possibly with some minor awareness of some pollution they don’t observe directly. Pollution, biodiversity, global warming, and so on don’t affect them today, but their behavior that causes it can improve their lives immediately. So how do we connect their behavior to something that matters more than their immediate comfort? To me you can point out how much money they have, future air quality, connection to nature, but eventually you end up at their children.

7. Fracking — My parents live in upstate New York where there is a lot of interest in fracking. First, let’s say someone figures out how to do it cleanly, without risking damaging the water supply, etc. How much would it help? Is there much benefit? Then, can you quantify the risks?

8. I don’t know if you’ve seen the Mr. Money Mustache blog — http://www.mrmoneymustache.com. You have an theme of “You can live just as happily, even more so, using a fraction of the energy you do now. You’ve just been sold on the idea that using energy creates happiness. The more you know, the more you can free yourself.” He has a similar attitude, substituting money for energy. I think you guys could do interesting cross posts. I think your communities would appreciate the similar underlying thinking and be able to realize how the same way their awareness led to financial independence could make them pollute a lot less and vice versa.

9. More personal — I’m interested to read what motivates you, how you choose what to post on, what debates you choose to enter, what goes on in your head as you spend time working on something that doesn’t pay you anything. We can all guess, but only you know.

10. A syllabus — have you thought about organizing what you’ve written about into a coherent, logical syllabus for high school or college teachers? Even posting the start of one might give others enough to customize for their purposes.

11. Population and efficiency — does efficiency matter if the population keeps growing? My gut says no, eventually no matter how efficient we are, population will eventually overwhelm efficiency. People need to eat, drink, stay warm, and dispose of their waste. More people need to do more of all that. That tells me no matter how efficient we make ourselves, we only forestall the inevitable need to decrease population growth. Doesn’t increasing efficiency make us more susceptible to otherwise small problems affecting everyone globally?

12. Biodiversity — not sure the math angle on this, but I’m curious about your thoughts. At a talk by E. O. Wilson on decreasing biodiversity I asked him if the decrease in biodiversity he talked about was also a decrease in biomass. That is, are there fewer plants and animals totally, or just fewer kinds. He said no, the biomass is not decreasing nearly as much. If we pave over a forest we lose biomass. If we create a monoculture we may /increase/ biomass. In terms of total life on earth, we may have increased it (if you value life, isn’t that /good/?), and if we can eat the monoculture, we have more food for people. I find that thinking specious, but I think many people accept it. Whatever the value of biodiversity (maybe we find cancer cures from some newly found species), I don’t think it’s nearly as clear to most as the value of creating a new farm from a forest.

13. The tragedy of the commons — I suspect all your readers know about the tragedy of the commons, but it lies at the base of most conversations about the environment, pollution, global warming, energy use, and so on. Individuals benefit at the potential expense of the larger community. I think it’s worth covering on your page.

That’s a lot. I’m sure I could come up with more. I’m happy to help with any of them.

I also want to second many previously suggestions (I may have overlapped several already) — comparing city/suburban/rural energy use on the same graph with different countries and a post that you’re writing a book, especially, or maybe a documentary, like on PBS.

Machine automation of just about everything, will commence eventually.
Of course, that cuts out most jobs, but the profit motive will do just that anyways (and it will do so to compete), at least until massive boycotts “votes” in other options.

What I’m getting at, though, is to have the machines mass produce the best energy choice.

Number 1 seems like advanced nuclear, however (and I don’t want to see robots making advanced nuclear facilities!) number 2, solar, would implement a lot of the reverse… machine made install jobs. Perhaps, at least to prolong “what will happen” after the age of complete machine (and computer programs) automation takes effect.

I know machines can make cars, thus they should be designed to make electric cars (which have fewer parts) and panels and batteries (which must have fewer parts still).

Therefore, a topic on the energy requirements of (the best kind of) machine made solar and batteries capable of powering ten billion people at near the western standard ( and with better efficiency) would be my favorite!